Folding apparatus

ABSTRACT

An improved folding apparatus for laundry articles being advanced by a conveyor having a pick up and drop, first folder, and leading and trailing photoelectric sensors at this folder for controlling its operation in response to the arrival of the leading and trailing edges of the article. The sensors also control a timing circuit for a second folder operating in two stages: beginning with the movement of the leading edge of the article past the trailing sensor; and beginning with the movement of the trailing edge of the article past the leading sensor.

United States Patent Gerstenberger et a1.

[ Dec. 16, 1975 [541 FOLDING APPARATUS [75] Inventors: Roland W. Gerstenberger; William E. Field, both of Fort Lauderdale, Fla.

[73] Assignee: Jensen Corporation, Fort Lauderdale, Fla.

[22] Filed: Dec. 13, 1973 [21] Appl. No.: 424,479

Related US. Application Data [63] Continuation-impart of Ser. No. 266,604, June 27, 1972, abandoned, which is a continuation-in-part of Ser. No. 190,812, Oct. 20, 1971, Pat. No. 3,714,459.

[52] US. Cl 270/62; 270/68 R; 270/86 [51] Int. Cl. B6511 45/12 [58] Field of Search 270/61 R, 62, 66, 69, 67, 270/80-82 [56] References Cited UNITED STATES PATENTS 2,177,262 10/1939 Neckel 270/66 2,329,353 9/1943 La Bombard.... 270/61 X 2,374,779 5/1945 Preston 1 270/81 2,643,879 6/1953 Spreckelmeier 270/81 2,969,233 1/1961 Buss 270/69 3,079,143 2/1963 Jensen 270/68 R 3,331,139 7/1967 Finnegan 34/45 3,339,578 9/1967 Smith 137/392 3,363,897 1/1968 Northern 270/69 X 3,552,736 1/1971 Frick 1 1 270/61 3,634,699 1/1972 COX 307/118 Primary ExaminerMelvin D. Rein Assistant ExuminerA. Heinz Attorney, Agent, or FirmOltman and Flynn [5 7 ABSTRACT 6 Claims, 19 Drawing Figures Dec. 16, 1975 Sheet 1 0f 6 VARIABLE CHARGE CIRCUIT 14s L H 1 1 J j 152 1 g sa US. Patent Dec. 16, 1975 Sheet 2 of 6 104 102 6 Bi 1.33 112 9a 120 132 Z Z 128 11a 12a .134 1oo n6 T 136 1 ii T a ns fng u She Dec.

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US, Pawn Dec. 16, 1975 Sheet 5 of6 3,926,424

zugaeo 1W ill FOLDING APPARATUS RELATED APPLICATION This application is a continuation-in part of our copending US patent application Ser. No. 266,604, filed June 27. l972 now abandoned, which was a continuation-in-part of our earlier filed US. Pat. application Ser. No. l90,8l2, filed Oct. 20, l97l, now US. Pat. No. 3,714,459.

BACKGROUND OF THE INVENTION Folding apparatus is known wherein two pick up and drop folders are employed to fold a laundry article in half and then in quarters. Sometimes cross folds are then made by further folding devices. In these known folders, the first two folding devices are in series on the same level of the apparatus, and they take up considerable space, thus making the apparatus quite wide. In-

SUMMARY OF THE INVENTION In accordance with the present invention, a folder apparatus is provided with a first folding device of the pick up and drop type and a second folding device of the roll type which substantially reduces the width of the apparatus as compared to known apparatus. Cooperating with these two folding devices is a timer which works in response to sensors at the first folder but controls the actuation of the second folder. The timer is preferably a variable charge rate type which measures a laundry article and then actuates the second folding device when the midpoint of the article reaches the fold point for the second folding device. The timer includes a capacitance which charges at one rate while measuring the article and then charges at a faster rate while tracking the midpoint (or other point) of the article to the fold point for the second folder.

Accordingly, it is an object of the present invention to provide a compact and reliable folding apparatus which is reduced in width as compared to known folding apparatus.

Another object of the invention is to combine a pick up and drop folder with a roll folder in a folding apparatus and time the roll folder off the pick up and drop folder.

Another object of the present invention is to actuate a timer by means of a sensor at a first folding device, with the timer in turn actuating a second folding device.

Another object of the invention is to measure an article while it is being folded in half.

A further object of the invention is to track the midpoint of the half folded article for a predetermined time at the end of which a folding device is actuated to fold the article in quarters.

Still another object of the invention is to tie a variable charge rate timer into a pick up and drop folding device so as to control a second folding device.

LII

Other objects of this invention will appear from the following description and appended claims, reference being had to the accompanying drawings forming a part of this specification wherein like reference characters designate corresponding parts in the several views.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of a laundry apparatus in which a variable charge rate timer is incorporated;

I FIG. 2 is a schematic diagram of a variable charge rate timer apparatus;

FIG. 3 is a schematic diagram of a portion of the circuit of FIG. 2;

FIG. 4 is a fragmentary schematic view of a portion of the apparatus of FIG. 1 showing a laundry article as its leading edge reaches a sensing means;

FIG. 5 is a schematic diagram similar to FIG. 4, but showing the laundry article when its trailing edge reaches the sensing means;

FIG. 6 is also a schematic diagram similar to FIG. 4, but showing the laundry article when its mid-portion reaches a predetermined position when folding of the article commences;

FIG. 7 is an elevational view of a laundry apparatus which includes a pick up and drop folding device followed by a roll type folding device and a timer operated by the first folding device to control the secondfolding device in accordance with the present invention;

FIG. 8 is a top plan view of the apparatus of FIG. 7;

FIG. 9 is a fragmentary sectional view of a portion of the apparatus taken along line 99 of FIG. 8 and looking in the direction of the arrows;

FIG. 10 is a cross sectional view of the apparatus taken along 10-10 of FIG. 8 and looking in the direction of the arrows;

FIG. 11 is a cross sectional view taken along line 11-11 of FIG. 8 and looking in the direction of the arrows;

FIG. 12 is a fragmentary cross sectional view similar to FIG. 10 showing a laundry article while it is being folded in half by the pick up and drop folding device;

FIG. 13 is another fragmentary sectional view showing the laundry article after it has been folded in half;

FIG. 14 shows the condition of the same apparatus after the half-folded laundry article has travelled until its midpoint has reached the fold point of the second or roll type folder;

FIG. 15 is another fragmentary sectional view showing the laundry article being folded into quarters by the second or roll type folder; FIG. 16 is another fragmentary sectional view showing the laundry article after it has travelled to a third folder which is also a roll type folder for making a cross fold;

FIG. 17 is a cross sectional view taken along line 17-l7 of FIG. 16 showing a cross fold being made by the third folder;

FIG. 18 is a circuit diagram which is similar to FIG. 2 but involves certain modifications; and

FIG. 19 is a circuit diagram of an amplifier included in FIG. 18.

Before explaining the presnet invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also, it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.

DETAILED DESCRIPTION A laundry apparatus 11 is shown schematically in FIG. I. Included in the apparatus ll is a variable charge rate timer 12, schematic diagrams for which are shown in FIGS. 2 and 3. It will be understood that the timer 12 is not limited in its utility to the particular laundry apparatus of FIG. 1, but this apparatus is a typical example of a suitable application for the variable charge rate timer.

In the laudnry apparatus 11, there is a conveyor loop 14 which passes around several rollers and includes an upper, generally horizontal flight 14 on which a laundry article is conveyed. The laundry article might be a towel, by way of example. At the entrance end of the apparatus, the conveyor 14 passes around a roller 18 and runs on an incline to another roller 20 where the horizontal upper flight 14' of the conveyor 14 begins. From roller 20, the upper flight 14' of the coveyor 14 extends to a roller 22 at the trailing end of the upper flight 14. From roller 22, the conveyor has a portion 24 extending generally downwardly and at an angle toward the front of the apparatus. The portion 24 terminates at a roller 26, and the conveyor passes around roller 26 to another roller 28, around roller 28, and back over rollers 30 and 32 to the entrance of the apparatus.

Two folding members 34 and 36 are mounted above the upper horizontal flight 14'. As the laundry article moves along the upper flight of the conveyor, its side edge portions ride upon folding members 34 and 36. These folding members are designed to fold the side edge portions of the article up, over and down on the mid-portion of the article to form a French fold. After the article is folded, it leaves the folding members 34 and 36 and continues to a position near the right end of the apparatus where the article 38 is shown in dashed lines in FIG. 1. At this position, the article is folded in half transversely by forcing it between rollers 22 and 40 with an air blast from a pneumatic device 42. It is the function of the variable charge rate timer to assure that the air blast from pneumatic device 42 is delivered at exactly the right time to force the mid-portion of the article between rollers 22 and 40. Of course, if the fold were desired at some point other than the mid-portion, the timer would be suitably adjusted to accomplish that, but in the illustrated embodiment the fold is made at the center of the article.

A separate conveyor loop 44 passes around rollers 40 and 26, and the upper flight of conveyor 44 contacts and runs parallel with conveyor flight 24. As the article passes between rollers 22 and 40, it is gripped between the conveyor portions 24 and 44, so the article passes down and to the left while travelling to roller 26. Then the article passes around roller 26 and into a discharge portion of the apparatus which includes still another k conveyor 46 which passes around rollers 48 and 50. The conveyor 46 presses on the top of the article and drags it along over a pair of plates 52 which are capable of opening in the manner of a trap door. The conveyor 46 stops at a proper time, and the doors 52 open to drop the article onto a table or into a bin or other suitable receptacle.

It may be seen that there is a photocell device 54 cooperating with a mirror 56, these elements being associated with the upper flight 14' of the conveyor 14. Referring to FIGS. 4, 5 and 6, the pohotocell device 54 is represented by an arrow. Only a portion of the apparatus is shown here to illustrate the principle of measuring and timing functions. In FIG. 4, a towel 38 is shown at the entrance end of the conveyor 14. The upper flight 14 of the conveyor is also shown, although it has been shortened relatively in FIG. 4 to simplify the drawings. The photocell 54 acts as a sensing means to sense the leading edge of the towel 38. Light from the photocell device 54 is blocked from the mirror 56 while the towel 38 passes under the photocell 54. As will be explained further, the variable charge rate timer 12 of FIGS. 2 and 3 measures the towel 38 while it traverses the photocell 54.

As shown in FIG. 5, when the trailing edge of the article 38 passes under the photocell 54, the light from the photocell is no longer blocked. This initiates a timing function of the timer 12 which times the operation of the pneumatic device 42.

As shown in FIG. 6, the towel 38 continues to move to the right while the timer 12 is timing the movement, and when the center of the towel 38 reaches the pneumatic device 42 and is directly over the rollers 22 and 40, the timer 12 actuates the pneumatic device 42 which then delivers a blast of air to force the center of the towel 38 between rollers 22 and 40. The rollers 22 and 40 nip the article and deliver it to the conveyor portions 24 and 44 which transport the article on through the apparatus.

Referring now to FIGS. 2 and 3, a power source 54 consists of a-c power lines 56, 58 and 60 which enter the circuit through a switch 62 and fuses 64. Lines 56 and 58 supply a-c power to the timer l2 and also to the motor (not shown) for operating the conveyors of the apparatus 11. The timer 12 includes a variable charge circuit 66 which is represented as a block in FIG. 2, but which is shown in a complete schematic diagram in FIG. 3. The terminals 1 through 10 of circuit 66 in FIG. 2 are the same as terminals 1 through 10 in FIG. 3.

The photocell 54 is associated with a relay switch 68, and the switch 68 and photocell 54 together constitute a switching means for sensing the laundry article 38. The switch 68 is shown in an amplifier 70 which is represented schematically by a block since the circuit is standard.

The control means 72 of the timer includes two relays 74 and 76 which control the operation of the variable charge circuit 66 as will be explained further. Output means includes a solenoid 78 which actuates a valve of the pneumatic device 42 to deliver a blast of air from device 42 for folding the laundry article 38. Other portions of the output means are included in the circuit 66.

The circuit 66, as shown in FIG. 3, includes a bridge rectifier 80 from which lines 82 and 84 supply d-c power to the circuit 66. The bridge rectifier 80 is connected by lines 86 and 88 through terminals 10 and 8 respectively to a transformer 90 (FIG. 2) through which a-c power is supplied to the rectifier 80. One end of the primary 92 of the transformer 90 is connected to line 58, and the other end of primary 92 is connected to a contact 94 of relay 76, and contact 94 cooperates with a movable contact 96 which is connected to the other power supply line 56. Contacts 94 and 96 are normally open, so when relay 76 is deenergized, no power is applied to the variable charge circuit 66.

Circuit 66 includes a zener diode 98 connected across lines 82 and 84 for regulating the voltage of the circuit. A capacitor 100 and a resistance 102 in the form.of a potentiometer are connected in series with each other across lines 82 and 84. Another resistance 104 in the form of a potentiometer is connected in parallel with resistance 102 to the capacitor 100. The line 106 which connects resistance 104 to capacitor 100 passes through terminals 7 and 6 of circuit 66, and it may be seen in FIG. 2 that terminals 7 and 6 are respectively connected to contacts 108 and 110 of relay 74. Contacts 108 and 110 are normally open when relay 74 is deenergized, so in the deenergized condition of relay 74, resistance 104 is disconnected from capacitor 100.

The relay 74 serves as a means to connect and disconnect the resistance 104 relative to the capacitor 100. When relay 74 is energized, both resistances 102 and 104 are connected in parallel with each other to capacitor 100. When relay 74 is deenergized, only resistance 102 is connected to capacitor 100. When power is applied to lines 82 and 84, capacitor 100 charges at a relatively slow rate through resistance 102. As will be explained, this charging occurs while the laundry article 38 traverses photocell 54. When photocell 54 senses the trailing edge of the article 38, the resistance 104 is connected in parallel with resistance 102 to the capacitor 100, and then the capacitor 100 charges at a faster rate while the laundry article travels to the pneumatic device 42. In this particular emobiment, the capacitor 100, when charging at the faster rate, charges twice as fast as when it is charging at the slower rate. This is because the effective resistance of resistances 102 and 104 in parallel is one-half that of resistance 102 alone. When the capacitor 100 charges to a predetermined voltage, it fires unijunction transistor 112 which is connected through resistors 114 and 116 across lines 82 and 84. The gate 118 of a silicon controlled rectifier 120 is connected to one of the base electrodes of unijunction transistor 1 12, and the output of unijunction transistor 112 fires the silicon controlled rectifier 120. The anode 122 of silicon controlled rectifier 120 is connected through line 124 and the coil 126 of relay 128 to the power line 82. Thus, when silicon controlled rectifier 120 fires, the relay 128 is energized. Coil 126 of relay 128 then closes contacts 130 and 132 of this relay. Contacts 130 and 132 are respectively connected by lines 134 and 136 through terminals 3 and 2 of circuit 66 to line 56 and to the solenoid 78 which in turn is connected to line 58. Thus, when relay 128 is energized, the solenoid 78 is actuated to produce the air balst which folds the article.

Transistor 112, controlled rectifier 120, relay 128 and solenoid 78 all form part of the output means of the timer.

Charging and discharging of the capacitor 100 is controlled by the control means 72 which includes relays 74 and 76. The switch 68 and photocell 54 cooperate with the control means. Switch 68 is part of a relay which includes contacts 140, 142 and 144. Contact 144 is connected through terminal 4 of amplifier 70 via line 146 to the coil of relay 74 and from there to line 58. Contacts 142 and 144 are normally closed, and contact 142 is connected through terminal 5 to line 56. With contacts I42 and 144 normally closed, the coil of relay 74 is energized. The energizing of relay 74 closes contacts 108 and 110 of that relay, thus connecting resistance 104 to capacitor 100. When the leading edge of the laundry article 38 passes under the photocell 54, light from the photocell 54 is blocked and this actuates the relay coil of switching device 68 to open contacts 142 and 144 and close contacts 140 and 142. The opening of contacts 142 and 144 deenergizes relay 74 to in turn open contacts 108 and and thus disconnect resistance 104 from capacitor 100. Therefore, while the laundry article 38 is traversing the photocell 54, capacitor 100 charges through resistance 102 at a relatively slow rate. The closing of contacts 140 and 142 energizes relay 76 because contact 140 is connected through terminal 6 and line 148 to the coil of relay 76 which is in turn connected to power line 58.

The energizing of relay 76 closes contacts 94 and 96 to supply power through transformer 92 to the bridge rectifier 80. This applies power to the circuit 66 so that the capacitor 100 can charge as previously mentioned. Prior to this time no power has been applied to circuit 66, so the capacitor 100 does not charge. Relay 76 has contacts 150 and 152 which are normally open, but which close when relay 76 is energized. Contact 152 is connected to line 148, and contact 150 is connected via line 154 through terminal 1 of circuit 66 and through normally closed contacts and 133 of relay 128 and line 134 through terminal 3 back to the power line 56. Thus, contacts 150 and 152 of relay 76 are latching contacts which hold the relay 76 energized, even after the laundry article finishes traversing the photocell 54.

Relay 76 also has contacts 156 and 158 which are normally closed, but which open when the relay 76 is energized. Contact 158 is connected to contact 110 which, as previously mentioned, serves to connect resistance 104 to capacitor 100. Contact 156 is connected via line .160 and terminal 5 of circuit 66 to the minus side of capacitor 100. When contacts 156 and 158 are closed, the minus side of capacitor 100 is connected through contact 158, line 159, terminal 6 and resistor 101 to the upper side of capacitor 100, so resistor 101 provides a discharge path for discharging the capacitor 100. However, when relay 76 is energized, contacts 156 and 158 open to disconnect this discharge path so that the capacitor can be charged.

As previously mentioned, relay 76 remains energized after the laundry article 38 finishes traversing photocell 54. However, switch 68 is deenergized, so contacts 142 and 144 again close and contacts and 142 open. The closing of contacts 142 and 144 energizes relay 74 to close contacts 108 and 110, and thus connect resistance 104 to capacitor 100. At this time, capacitor 100 begins charging at twice the rate at which it charges when current is supplied to it only through resistance 102. The capacitor 100 continues charging at this faster rate until it reaches a voltage at which unijunction transistor 112 fires, and this ultimately operates the solenoid 78 to cause a blast of air to fold the laundry article 38 as previously described. In this sequence of operation, relay 128 is energized to close contacts 130 and 132 and open contacts 130 and 133. The opening of contacts 130 and 133 interrupts the power circuit of relay 76, so relay 76 is deenergized. This causes contacts 156 and 158 to close, thus completing the discharge path through resistor 101 for capacitor 100, and allowing the capacitor 100 to discharge back to its initial condition. Contacts 94 and 92 open to remove power from circuit 66, and contacts and 152 open to unlatch the relay 76. The control means 72 has now returned to its initial condition.

With the foregoing arrangement (disregarding various time delays in the apparatus), the distance along the conveyor from the photocell 54 to the folder 22, 40, 42, where the laundry piece is to be folded at its longitudinal midpoint, is directly proportional to the 7 firing or triggering voltage for the unijunction 112. This relationship is the same for laundry pieces of different lengths.

The voltage on the capacitor 100 (which is to trigger the unijunction 112) may be expressed as follows:

V RT where R is the charging rate, and T is the time of charging. For a constant speed conveyor, time (T) is proportional to the distance through which a laundry piece is advanced by the conveyor. All conveyors used in laundry folding equipment are operated at constant speed; otherwise, the timing of the different folding operations could not be precisely controlled in the desired manner. Therefore, T= K distance (where K is a constant of proportionality).

With L as the length of the laundry piece, S as the distance from the photocell 54 to the folder, r, as the slow charging rate (while the laundry piece is moving past the photocell), and 2r, as the fast charging rate (after the laundry piece has moved completely past the photocell), the capacitor voltage required to trigger the unijunction 112 may be expressed as follows (in terms of charging rate and elapsed time):

This shows the direct relationship between the unijunction triggering voltage and the distance along the conveyor from the photocell 54 to the folder, whatever the length (L) of the laundry piece.

In the foregoing equation (I), the first term, r KL, represents the voltage build-up on the capacitor 100 which takes place while the laundry piece is moving past the photocell 54 and the capacitor is being charged through resistor 102 only. The second term, 2r K (S /2L), represents the further voltage build-up on the capacitor which takes place (at the faster charg ing rate, 2r between the time when the trailing edge of the laundry piece moves past the photocell 54 and the time when the longitudinal midpoint of the laundry piece reaches the location of the folding operation.

The broad principle of operating the timing circuit for a laundry folder in two stages, the first being the interval while the laundry piece is moving past a photocell or other sensor. and the second being the interval which immediately follows until the middle of this laundry piece reaches the following folder, may be understood from the disclosure in US. Pat. No. 2,374,779 to Preston.

FIGSv 7-19 illustrate another embodiment of the in vention. Referring first to FIGSv 7 and 8, there is shown a folding apparatus 200 which includes a motor driven conveyor in the form of belts 202 looped around shafts 204 and 206. Conveyor belts 202 are on the upper level of the apparatus 200, and they transport a laundry article along a generally horizontal path from shaft 204 to shaft 206. FIG. 11 shows that shaft 206 may be driven by a motor 208 utilizing a drive chain 210 and sprockets 212, 214, 216 and 218. Other shafts 220, 222 and 224 may be utilized in connection with the upper conveyor flight formed by belts 202.

Referring to FIGS. 10 and 12, it may be seen that there is a second conveyor flight 226 below the upper conveyor flight 202. The conveyor flight 226 is simi larly formed by belts looped about shafts 228 and 230. The second conveyor flight 226 may be operated by a motor 232 (FIG. 11) connected by a chain 234 to the shaft 230 utilizing sprockets 236 and 238.

Above the upper conveyor flight 202, there is a first folding device 240, which in this embodiment is a pick up and drop type of folding device. Referring to FIG. 9, it may be seen that the folding device 240 includes a blade 242 which is pivoted at 244 and is connected to an arm 246 that is driven by a piston 248 in a cylinder 250. Pressure is supplied to the cylinder 250 through a valve 252 which controls the supply of fluid through a line 254 and the return of fluid through another line 256. The valve 252 is actuated in response to switching means which in this embodiment consists of two photocells 258 and 260. Photocells 258 and 260 have light sources 262 and 264 which shine light on mirrors 266 and 268. The light is reflected back to sensors 270 and 272 inside the photocells 258 and 260. When the light is shining on the mirrors and being reflected back to the sensors 270 and 272, the electrical resistance of the sensors is relatively low, and when the light is interrupted so that it does not reach the sensors 270 and 272, the resistance of the sensors increases. This change in resistance of the sensors is utilized to control the valve 252 so as to operate the blade 242. When light is reaching the sensors and their resistance is low, the blade 242 is down in the position shown in FIG. 9. When the light is interrupted so that it does not reach the sensors 270 and 272, the sensors actuate the valve 252 which in turn supplies fluid to the cylinder 250 to push the piston 248 to the left and thus raise the blade 252 until it contacts a stop 274. As the blade rises, it clamps the leading edge of a laundry article against the stop 274. When the trailing edge of the article passes the photocell 260, the resistance of sensor 272 changes again to the low value, and this causes valve 252 to reverse and allow fluid to exit from chamber 250 so that the blade 242 drops back to the position shown in FIG. 9. This deposits the leading edge of the laundry article on the trailing edge thereof, thus folding the article in half.

The folding of a laundry article in this manner may be seen in successive stages shown in FIGS. l0, l2 and 13. In FIG. 10, a laundry article 276 has travelled along the upper conveyor flight 202 until the leading edge 278 of the article has ridden up on blade 242 and interrupted the light of both photocells 258 and 260. The blade 242 then rises to clamp the leading edge 278 against the stop 274 in the manner shown in FIG. 12, thus retaining the leading edge while the rest of the article travels along the upper conveyor flight 202. In FIG. 13, the article has travelled until it is almost folded in half, and the trailing edge 280 is about to pass under the photocell 260. When this happens, the blade 242 drops down and deposits the leading edge 278 on the trailing edge 280 so that the article is folded in half and continues to travel along the upper conveyor flight 202 as shown in FIG. 14.

In FIG. 14, the laundry article 276 has reached a position where its quarter point 282 has reached a fold point between two rolls or shafts 206 and 230 of a second folding device which is a roll type of folder. This second folding device includes an operator means in the form of pneumatic tube 284 for forcing the quarter point 282 between the rolls 206 and 230 in the manner shown in FIG. 15. To accomplish this. the tube 284 delivers a blast of air against the quarter point 282 exactly when that quarter point reaches the fold point between rolls 206 and 230. It will be understood that in some applications it may be possible to employ an operator means in some other form such as a blade in order to 9 force the laundry article betweenthe rolls 206 and 230.

The timing of the actuation of the pneumatic operator means 284 is accomplished by the circuits of FIGS. 18 and 19 in conjunction with the circuit of FIG. 3 described previously. These circuits will be described in detail later herein, but at present, the description of the overall machine will be completed.

Referring to FIG. 16, it may be seen that the laundry article 276, after passing between the rolls 206 and 230, is folded in quarters and travels along the second conveyor flight 226 toward the right as viewed in the drawings. The article 276 reaches a center position with respect to a second pneumatic operator means 286 which is located above the second conveyor flight 226. The pneumatic operator means ortube 286 is shown in cross section in FIG. 17. When the article reaches this center position, the pneumatic tube 286 is actuated to deliver a blast of air which forces thearticle between two rolls 288 and 290 which are located just under the upper run of the conveyor 226. Thus, these rolls 288 and 290 make a cross fold in the article. From rolls 288 and 290, the article travels-down a curving ramp 289 which may deliver the article to still another conveyor (not shown). Additional pick up and drop folding devices may be provided along this latter conveyor if additional cross folds are desired. These additional folding devices are not shown since they do not form a part of the present invention. Also, it will be understood that the pneumatic operator means 286 is operated by a sensing means such as a photocell which is interrupted when the article reaches the center position shown in FIG. 16. This latter photocell is not shown.

Referring now to FIGS. 18 and 19 considered together with FIG. 3, it is to be understood that FIG. 18 is almost identical to FIG. 2, and therefore the same reference numerals have been used for like parts. One difference is that several power supply connections have been replaced by 24 volt terminalssuch as 292, 294, 296 and 298 as shown in FIG. 18. Also, the two photocell devices 258 and 260 including the sensore 270 and 272 are shown in FIG. 18. Except for these differences, the circuit of FIG. l8 operates exactly like that described in connection with FIG. 2, so the description will not be repeated.

FIG. 19 also shows the two photocell devices 258 and 260 with their sensors 270 and 272. These photocell devices are the switching means of thefirst folding device 240, but they also actuate the timer means which consists of the circuits of FIGS. 3, l8 and 19. FIG. 19 actually shows the amplifier circuit which is block 70 in FIG. 18. The input of the amplifier is a transformer 300 having a primary winding 302 and a secondary winding 304. A voltage of about 230 volts may be developed across the secondary winding 304, and a portion of this voltage is supplied to lines 306 and 308.

The circuit of FIG. 19 includes two amplifying transistors 310 and 312, the output of transistor 312 is connected to a relay which includes a coil 314. The relay 314 also includes a contact 316 which is connected to the photocells 258 and 260, contacts 318, 320 and 322 which control the valve 252 of FIG. 9, and also contacts 140, 142 and 144 which are shown in FIG. 18 as being connected to the control means 72 of that circult.

A voltage divider including resistances 324 and 326 is connected between line 306 and the collector of transistor 310. A zener diode 330 is connected between the junction 328 of resistors 324 and 326 and the line 308 for regulating the voltage between those points. The emitters of transistors 310 and 312 are both connected through a diode 332 to the line 308. Resistors 334 and 336 together form a bias network for the base of transistor 310, and resistors 338 and 340 form a bias network for the transistor 312. The sensors 270 and 272 of photocells 258 and 260 are connected in paral-' lel with each other between junction 328 and the resistor 334 for biasing the base of transistor 310. A capacitor 342 is connected between lines 306 and 308 for filtering, and diodes 344 and 346 are connected to secondary winding 304 to provide rectification of the voltage on that winding.

In operation, while light is reaching both of the sensors 270 and 272, their effective resistance is low, and the amplifiers 310 and 312 do not pull in the relay 314. When the light of both of the photocells 258 and 260 is blocked, the resistances of sensors 270 and 272 increase and this puts more bias resistance between the collector and base of transistor 310, thus causing the base of transistor 310 to go more positive. Photocell 260, when blocked alone, does not actuate relay 214 because the lower resistance of photocell 2S8 shunts it. Transistor 310 then conducts less current, and since the current through diode 332 is shared between transistors 310 and 312, transistor 312 conducts more strongly, thus pulling in relay 314. Contact 316 then opens to disconnect the trailing photocell 258. At this time the impedance of the leading photocell is such that the bias resistance between the collector and base of transistor 310 is high enough to keep relay 314 energized. Contacts 318, 320 and 322 are operated to actuate the valve 252 as previously explained. Contacts 142 and 144 are opened, and contacts 140 and 142 are closed to start the measuring cycle which has been explained in connection with FIG. 3. The capacitor of FIG. 3 charges at a slow rate during the measuring cycle.

Ultimately the trailing edge of the laundry article passes over the leading photocell device 260, and this then lowers theresistance in the bias circuit for the base of transistor 310. Transistor 310 then conducts more, and transistor 312 conducts less so as to drop out the relay 314. The contacts 316, 318, 320 and 322 and 141 then return to their original conditions. This ends the measuring cycle of the timing circuit of FIG. 18 and FIG. 3. The capacitor 100 of FIG. 3 then charges at a rate four times as great as its initial charging rate and causes the pneumatic operator means 284 to be actuated so as to force the laundry article 276 between the rolls 206 and 230 when the quarter point 282 reaches the fold point opposite tube 284 as previously explained.

It is to be understood that the capacitor 100 of FIG. 3 must charge at a first slow rate while the laundry article traverses photocell devices 258 and 260 and then charge at quadruple this rate while the laundry article travels along conveyor 202 until the quarter point 282 of the laundry article reaches the fold point opposite pneumatic operator means 284. The conveyor should travel at a constant speed. i

It may also be noted that the unijunction transistor 112 in FIG. 3 is a discharge device, and it may be replaced by other types of discharge devices. For example, it has been found that a voltage comparator in the form of an integrated circuit can be used in place of the unijunction transistor 1 l2, and the voltage comparator allows easy adjustment of the firing threshold of the dis- 1 1 charge device. This adjustment is made while observing the folding operation until the quarter fold is made at the correct point.

From the foregoing description, it may be seen that the combination of a roll type folding device with a. pick up and drop folding device along the upper flight of the apparatus reduces the width of the apparatus, thus making it possible to install the apparatus in cramped quarters such as are sometimes found in hotels and other establishments having limited laundry space. The laundry articles are fed by hand into the apparatus, and the articles can be folded as fast as they can be fed. The timer for controlling the actuation of the second folding device works off the switching means and blade for the first folding device, so no additional switches or sensors are required. The variable charge rate timer is well suited to the timing functions of the apparatus, and provides reliable actuation of the second folding device.

Having thus described our invention, we claim:

1. A folding apparatus for folding laundry articles and comprising:

means for transporting a laundry article along a predetermined path,

a pick up and drop folder positioned along said path, for folding the article, said folder having a blade for lifting and retaining the leading edge of the article and thereafter dropping said leading edge on the trailing edge of the article as it moves past, and means to raise said blade for lifting and retaining the leading edge of the article and to lower said blade for dropping and releasing the leading edge of the article,

a roll folder positioned along said path beyond said pick up and drop folder for folding the article again,

timer means controlling the operation of said roll folder, and

sensor means at said pick up and drop folder for sensing successively the movement of the leading and trailing edges of the article past it, said sensor means being operably coupled to both said pick up and drop folder and said timing means for the roll folder:

a. to cause said blade in the pick up and drop folder to be raised in response to the movement of the leading edge of the article past said sensor means;

b. to cause said blade to be lowered in response to the movement of the trailing edge of the article past said sensor means; and

c. in response to the movement of the leading and trailing edges of the article in succession past said sensor means, to actuate said timer means to cause said roll folder to fold the article as it moves past;

said sensor means comprising a leading sensor positioned to sense the leading edge of the article before it reaches said blade, and a trailing sensor positioned to sense the leading edge of the article after it reaches said blade, and further comprising relay means responsive to both the leading sensor and the trailing sensor to cause the blade in the pick up and drop folder to be raised when both sensors have sensed the leading edge of the article.

said relay means including contacts for automatically disconnecting the same from said trailing sensor after the latter senses the leading edge of the article and for atuomatically reconnecting the same to said trailing sensor after the leading sensor senses the trailing edge of the article, said relay means having further contacts;

said timer means including capacitance means adapted to be electrically charged and discharged, and control circuit means actuated by said further contacts of said relay means for charging said capacitance means at a slow rate beginning with the movement of the leading edge of the article past the trailing sensor and at a quadrupled rate beginning with the movement of the trailing edge of the article past the leading sensor so as to time the operation of said roll folder for folding the oncefolded article again at the middle.

2. Apparatus according to claim 1 in which said relay means includes a relay, and amplifier means connected between said relay and said sensors for controlling said relay. 1

3. Apparatus according to claim 2 in which said amplifier means includes a pair of emitter coupled transistors having a bias network including said sensors.

4. Apparatus according to claim 3 in which said sensors are coupled in parallel with each other in said bias network, and said contacts are operable to disconnect and reconnect said trailing sensor from said bias network.

5. A folding apparatus for folding laundry articles comprising:

means for transporting a laundry article along a predetermined path,

a pick up and drop folder positioned along said path for folding the article, said folder having a blade for lifting and retaining the leading edge of the article and thereafter dropping said leading edge on the trailing edge of the article as it moves past, and means to raise said blade for lifting and retaining the leading edge of the article and to lower said blade for dropping and releasing the leading edge of the article,

a roll folder positioned along said path beyond said pick up and drop folder for folding the article again,

timer means controlling the operation of said roll folder, and

sensor means at said pick up and drop folder for sensing successively the movement of the leading and trailing edges of the article past it, said sensor means being operably coupled to both said pick up and drop folder and said timing means for the roll folder:

a. to cause said blade in the pick up and drop folder to be raised in response to the movement of the leading edge of the article past said sensor means;

b. to cause said blade to be lowered in response to the movement of the trailing edge of the article past said sensor means; and

c. in response to the movement of the leading and trailing edges of the article in succession past said sensor means, to actuate said timer means to cause said roll folder to fold the article as it moves past;

said sensor means comprising a leading sensor positioned to sense the leading edge of the article before it reaches said blade, and a trailing sensor positioned to sense the leading edge of the article after it reaches said blade;

and means responsive to both the leading sensor and the trailing sensor to cause the blade in the pick up and drop folder to be raised when both sensors have sensed the leading edge of the article, said last mentioned means being automatically disconnected from said trailing sensor after the latter senses the leading edge of the article,

said timer means including capacitance means 6. A folding apparatus for folding laundry articles comprising:

means for transporting a laundry article along a predetermined path,

a pick up and drop folder positioned along said path for folding the article, said folder having a blade for lifting and retaining the leading edge of the article and thereafter dropping said leading edge on the trailing edge of the article as it moves past, and means to raise said blade for lifting and retaining the leading edge of the article and to lower said blade for dropping and releasing the leading edge of the article,

a roll folder positioned along said path beyond said pick up and drop folder for folding the article again,

timer means controlling the operation of said roll folder, and

sensor means at said pick up and drop folder for sensing successively the movement of the leading and trailing edges of the article past it, said sensor means being operably coupled to both said pick up and drop folder and said timing means for the roll folder:

a. to cause said blade in the pick up and drop folder to be raised in response to the movement of the leading edge of the article past said sensor means;

b. to cause said blade to be lowered in response to the movement of the trailing edge of the article past said sensor means; and

c. in response to the movement of the leading and trailing edges of the article in succession past said sensor means, to actuate said timer means to cause said roll folder to fold the article as it moves past;

said sensor means comprising a leading sensor positioned to sense the leading edge of the article before it reaches said blade, and a trailing sensor positioned to sense the leading edge of the article after it reaches said blade, and means responsive to both the leading sensor and the trailing sensor to cause the blade in the pick up and drop folder to be raised when both sensors have sensed the leading edge of the article, said last-mentioned means being automatically disconnected from said trailing sensor after the latter senses the leading edge of the article,

said timer means including capacitance means adapted to be electrically charged and discharged, and means for changing the charge on said capacitance means at a slow rate beginning with the movement of the leading edge of the article past the trailing sensor and, beginning with the movement of the trailing edge of the article past the leading sensor, at a rate equal to said slow rate multiplied by a selected number effective to time the operation of said roll folder for folding the oncefolded article again at the middle. 

1. A folding apparatus for folding laundry articles and comprising: means for transporting a laundry article along a predetermined path, a pick up and drop folder positioned along said path, for folding the article, said folder having a blade for lifting and retaining the leading edge of the article and thereafter dropping said leading edge on the trailing edge of the article as it moves past, and means to raise said blade for lifting and retaining the leading edge of the article and to lower said blade for dropping and releasing the leading edge of the article, a roll folder positioned along said path beyond said pick up and drop folder for folding the article again, timer means controlling the operation of said roll folder, and sensor means at said pick up and drop folder for sensing successively the movement of the leading and trailing edges of the article past it, said sensor means being operably coupled to both said pick up and drop folder and said timing means for the roll folder: a. to cause said blade in the pick up and drop folder to be raised in response to the movement of the leading edge of the article past said sensor means; b. to cause said blade to be lowered in response to the movement of the trailing edge of the article past said sensor means; and c. in response to the movement of the leading and trailing edges of the article in succession past said sensor means, to actuate said timer means to cause said roll folder to fold the article as it moves past; said sensor means comprising a leading sensor positioned to sense the leading edge of the article before it reaches said blade, and a trailing sensor positioned to sense the leading edge of the article after it reaches said blade, and further comprising relay means responsive to both the leading sensor and the trailing sensor to cause the blade in the pick up and drop folder to be raised when both sensors have sensed the leading edge of the article. said relay means including contacts for automatically disconnecting the same from said trailing sensor after the latter senses the leading edge of the article and for atuomatically reconnecting the same to said trailing sensor after the leading sensor senses the trailing edge of the article, said relay means having further contactS; said timer means including capacitance means adapted to be electrically charged and discharged, and control circuit means actuated by said further contacts of said relay means for charging said capacitance means at a slow rate beginning with the movement of the leading edge of the article past the trailing sensor and at a quadrupled rate beginning with the movement of the trailing edge of the article past the leading sensor so as to time the operation of said roll folder for folding the once-folded article again at the middle.
 2. Apparatus according to claim 1 in which said relay means includes a relay, and amplifier means connected between said relay and said sensors for controlling said relay.
 3. Apparatus according to claim 2 in which said amplifier means includes a pair of emitter coupled transistors having a bias network including said sensors.
 4. Apparatus according to claim 3 in which said sensors are coupled in parallel with each other in said bias network, and said contacts are operable to disconnect and reconnect said trailing sensor from said bias network.
 5. A folding apparatus for folding laundry articles comprising: means for transporting a laundry article along a predetermined path, a pick up and drop folder positioned along said path for folding the article, said folder having a blade for lifting and retaining the leading edge of the article and thereafter dropping said leading edge on the trailing edge of the article as it moves past, and means to raise said blade for lifting and retaining the leading edge of the article and to lower said blade for dropping and releasing the leading edge of the article, a roll folder positioned along said path beyond said pick up and drop folder for folding the article again, timer means controlling the operation of said roll folder, and sensor means at said pick up and drop folder for sensing successively the movement of the leading and trailing edges of the article past it, said sensor means being operably coupled to both said pick up and drop folder and said timing means for the roll folder: a. to cause said blade in the pick up and drop folder to be raised in response to the movement of the leading edge of the article past said sensor means; b. to cause said blade to be lowered in response to the movement of the trailing edge of the article past said sensor means; and c. in response to the movement of the leading and trailing edges of the article in succession past said sensor means, to actuate said timer means to cause said roll folder to fold the article as it moves past; said sensor means comprising a leading sensor positioned to sense the leading edge of the article before it reaches said blade, and a trailing sensor positioned to sense the leading edge of the article after it reaches said blade; and means responsive to both the leading sensor and the trailing sensor to cause the blade in the pick up and drop folder to be raised when both sensors have sensed the leading edge of the article, said last mentioned means being automatically disconnected from said trailing sensor after the latter senses the leading edge of the article, said timer means including capacitance means adapted to be electrically charged and discharged, and means for changing the charge on said capacitance means at a slow rate beginning with the movement of the leading edge of the article past the trailing sensor and at a quadrupled rate beginning with the movement of the trailing edge of the article past the leading sensor so as to time the operation of said roll folder for folding the once-folded article again at the middle.
 6. A folding apparatus for folding laundry articles comprising: means for transporting a laundry article along a predetermined path, a pick up and drop folder positioned along said path for folding the article, said folder having a blade for lifting and retaining the leading edge of the article and thereafter dropping said Leading edge on the trailing edge of the article as it moves past, and means to raise said blade for lifting and retaining the leading edge of the article and to lower said blade for dropping and releasing the leading edge of the article, a roll folder positioned along said path beyond said pick up and drop folder for folding the article again, timer means controlling the operation of said roll folder, and sensor means at said pick up and drop folder for sensing successively the movement of the leading and trailing edges of the article past it, said sensor means being operably coupled to both said pick up and drop folder and said timing means for the roll folder: a. to cause said blade in the pick up and drop folder to be raised in response to the movement of the leading edge of the article past said sensor means; b. to cause said blade to be lowered in response to the movement of the trailing edge of the article past said sensor means; and c. in response to the movement of the leading and trailing edges of the article in succession past said sensor means, to actuate said timer means to cause said roll folder to fold the article as it moves past; said sensor means comprising a leading sensor positioned to sense the leading edge of the article before it reaches said blade, and a trailing sensor positioned to sense the leading edge of the article after it reaches said blade, and means responsive to both the leading sensor and the trailing sensor to cause the blade in the pick up and drop folder to be raised when both sensors have sensed the leading edge of the article, said last-mentioned means being automatically disconnected from said trailing sensor after the latter senses the leading edge of the article, said timer means including capacitance means adapted to be electrically charged and discharged, and means for changing the charge on said capacitance means at a slow rate beginning with the movement of the leading edge of the article past the trailing sensor and, beginning with the movement of the trailing edge of the article past the leading sensor, at a rate equal to said slow rate multiplied by a selected number effective to time the operation of said roll folder for folding the once-folded article again at the middle. 